PFO closure device with flexible thrombogenic joint and improved dislodgement resistance

ABSTRACT

The present invention provides devices for closing septal defects, such as a patent foramen ovale (PFO). The closure devices include a proximal anchor member, a distal anchor member, and at least one flexible center joint connecting the two anchor members. According to some embodiments, the proximal and/or distal anchor members may include a generally cylindrical member split along the central portion of its length to form an elongate oval. The proximal and/or distal anchor members may further include a tissue scaffold. At least some of the closure devices according to the present invention are repositionable and retrievable.

RELATED APPLICATIONS

[0001] This application is a continuation-in-part of U.S. applicationSer. No. 10/326,535, filed Dec. 19, 2002, which claims the benefit ofU.S. Provisional Application No. 60/340,858, filed on Dec. 19, 2001.

FIELD OF THE INVENTION

[0002] The present invention relates generally to an occlusion devicefor the closure of physical anomalies, such as a patent foramen ovale.

BACKGROUND OF THE INVENTION

[0003] A patent foramen ovale (PFO), illustrated in FIG. 1, is apersistent, one-way, usually flap-like opening in the wall between theright atrium 10 and left atrium 12 of the heart. Because left atrial(LA) pressure is normally higher than right atrial (RA) pressure, theflap usually stays closed. Under certain conditions, however, rightatrial pressure can exceed left atrial pressure, creating thepossibility that blood could pass from the right atrium 10 to the leftatrium 12 and blood clots could enter the systemic circulation. It isdesirable that this circumstance be eliminated.

[0004] The foramen ovale serves a desired purpose when a fetus isgestating in utero. Because blood is oxygenated through the umbilicalchord, and not through the developing lungs, the circulatory system ofthe fetal heart allows the blood to flow through the foramen ovale as aphysiologic conduit for right-to-left shunting. After birth, with theestablishment of pulmonary circulation, the increased left atrial bloodflow and pressure results in functional closure of the foramen ovale.This functional closure is subsequently followed by anatomical closureof the two over-lapping layers of tissue: septum primum 14 and septumsecundum 16. However, a PFO has been shown to persist in a number ofadults.

[0005] The presence of a PFO is generally considered to have notherapeutic consequence in otherwise healthy adults. Paradoxicalembolism via a PFO is considered in the diagnosis for patients who havesuffered a stroke or transient ischemic attack (TIA) in the presence ofa PFO and without another identified cause of ischemic stroke. Whilethere is currently no definitive proof of a cause-effect relationship,many studies have confirmed a strong association between the presence ofa PFO and the risk for paradoxical embolism or stroke. In addition,there is significant evidence that patients with a PFO who have had acerebral vascular event are at increased risk for future, recurrentcerebrovascular events.

[0006] Accordingly, patients at such an increased risk are consideredfor prophylactic medical therapy to reduce the risk of a recurrentembolic event. These patients are commonly treated with oralanticoagulants, which potentially have adverse side effects, such ashemorrhaging, hematoma, and interactions with a variety of other drugs.The use of these drugs can alter a person's recovery and necessitateadjustments in a person's daily living pattern.

[0007] In certain cases, such as when anticoagulation iscontraindicated, surgery may be necessary or desirable to close a PFO.The surgery would typically include suturing a PFO closed by attachingseptum secundum to septum primum. This sutured attachment can beaccomplished using either an interrupted or a continuous stitch and is acommon way a surgeon shuts a PFO under direct visualization.

[0008] Umbrella devices and a variety of other similar mechanicalclosure devices, developed initially for percutaneous closure of atrialseptal defects (ASDs), have been used in some instances to close PFOs.These devices potentially allow patients to avoid the side effects oftenassociated with anticoagulation therapies and the risks of invasivesurgery. However, umbrella devices and the like that are designed forASDs are not optimally suited for use as PFO closure devices.

[0009] Currently available septal closure devices present drawbacks,including technically complex implantation procedures. Additionally,there are not insignificant complications due to thrombus, fractures ofthe components, conduction system disturbances, perforations of hearttissue, and residual leaks. Many devices have high septal profile andinclude large masses of foreign material, which may lead to unfavorablebody adaptation of a device. Given that ASD devices are designed toocclude holes, many lack anatomic conformability to the flap-likeanatomy of PFOs. Thus, when inserting an ASD device to close a PFO, thenarrow opening and the thin flap may form impediments to properdeployment. Even if an occlusive seal is formed, the device may bedeployed in the heart on an angle, leaving some components insecurelyseated against the septum and, thereby, risking thrombus formation dueto hemodynamic disturbances. Finally, some septal closure devices arecomplex to manufacture, which may result in inconsistent productperformance.

[0010] The present invention is designed to address these and otherdeficiencies of prior art septal closure devices.

BRIEF SUMMARY OF EMBODIMENTS OF THE INVENTION

[0011] Various embodiments of the present invention are directed todevices for closing septal defects such as PFOs. The closure devicesgenerally include a proximal anchor member, a distal anchor member, anda flexible center joint connecting the two anchor members. The centerjoint may be one or more sutures. Alternatively, the center joint may bea flexible elastomeric layer, which may promote tissue ingrowth ordeliver drugs. The flexible material may also be covered with abiocompatible material to promote adherence to tissue or with growthfactors to accelerate tissue ingrowth.

[0012] In accordance with some embodiments of the invention, the closuredevice is formed of bioresorbable components such that substantially nopermanent foreign material remains in the body.

[0013] In accordance with other embodiments of the invention, theproximal and/or distal anchor members of the closure device may includea generally cylindrical member split along the center portion of itslength to form an elongate oval when the ends of the member are pressedtogether. Of course, a variety of cross section shapes in addition to acircular cross section may be used. Such proximal and/or distal anchormembers may be two-dimensional or three-dimensional. Such proximaland/or distal anchor members may further include a tissue scaffold.

[0014] In accordance with further embodiments of the invention,mechanisms are provided to collapse the closure device in order tofacilitate device delivery, removal and/or repositioning.

[0015] These and other features will become readily apparent from thefollowing detailed description wherein embodiments of the invention areshown and described by way of illustration. As will be realized, theinvention is capable of other and different embodiments and its severaldetails may be capable of modifications in various respects, all withoutdeparting from the invention. Accordingly, the drawings and descriptionare to be regarded as illustrative in nature and not in a restrictive orlimiting sense.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016]FIG. 1 is a cross-sectional view of a portion of the heartillustrating a PFO;

[0017]FIG. 2 illustrates a deployed PFO closure device withbioresorbable components in accordance with one or more embodiments ofthe invention;

[0018]FIG. 3 illustrates the PFO closure device of FIG. 2 in a collapsedstate for passage through a delivery catheter or sheath;

[0019]FIG. 4 illustrates a closure device deployed to close a PFO inaccordance with one or more further embodiments of the invention;

[0020]FIG. 5 illustrates a closure device deployed to close the PFO inaccordance with one or more further embodiments of the invention;

[0021]FIGS. 6A and 6B are front and side views, respectively, of a PFOclosure device in accordance with one or more further embodiments of theinvention;

[0022]FIGS. 7A and 7B are front and side views, respectively, of a PFOclosure device in accordance with one or more further embodiments of theinvention;

[0023]FIGS. 8A and 8B are side and front views, respectively, of the PFOclosure device of FIG. 6 deployed to close a PFO;

[0024]FIG. 9A illustrates a closure device having a retrieval mechanismin accordance with one or more further embodiments of the invention in acollapsed state for passage through a catheter or sheath;

[0025]FIG. 9B is a front view of the FIG. 9A device;

[0026] FIGS. 9C-E illustrate deployment of the FIG. 9A device;

[0027] FIGS. 9F-H illustrate removal of the FIG. 9A device;

[0028]FIG. 10A illustrates a closure device having a retrieval mechanismin accordance with one or more further embodiments of the invention in acollapsed state for passage through a catheter or sheath;

[0029]FIG. 10B is a front view of the FIG. 10A device;

[0030]FIGS. 11A and 11B illustrate an anchor member with an elastichinge in accordance with one or more further embodiments of theinvention;

[0031]FIG. 12 illustrates a PFO closure device made from a singlematerial in accordance with one or more further embodiments of theinvention;

[0032]FIG. 13 illustrates a PFO closure device having inflatable anchormembers in accordance with one or more further embodiments of theinvention;

[0033]FIG. 14 illustrates a PFO closure device with a wire connectingthe proximal and distal anchor members in accordance with one or morefurther embodiments of the invention;

[0034]FIG. 15 illustrates a PFO closure device having a frame member inaccordance with one or more further embodiments of the invention;

[0035]FIG. 16 illustrates a PFO closure device having frame anchormembers in accordance with one or more further embodiments of theinvention;

[0036]FIG. 17 illustrates a PFO closure device having frame anchormembers in accordance with one or more further embodiments of theinvention;

[0037]FIG. 18 illustrates the FIG. 17 device in a collapsed state forpassage through a catheter or sheath;

[0038]FIG. 19 illustrates a frame anchor member having metal and polymercomponents in accordance with one or more further embodiments of theinvention;

[0039]FIGS. 20A and 20B illustrate a PFO closure device having anchormembers formed from a rolled material in accordance with one or morefurther embodiments of the invention in rolled and unrolled positions,respectively;

[0040]FIGS. 21A and 21B illustrate an alternate PFO closure devicehaving anchor members formed from a rolled material in accordance withone or more further embodiments of the invention in rolled and unrolledpositions, respectively;

[0041]FIG. 22A illustrates a closure device having frame anchor membersand a generally “X” shaped joint member in accordance with one or morefurther embodiments of the invention;

[0042]FIG. 22B illustrates the proximal anchor member of the FIG. 22Adevice;

[0043]FIG. 22C illustrates the FIG. 22A device in a deployed state;

[0044]FIG. 23 illustrates a closure device having frame anchor membershaving a generally “+” shaped frame structure in accordance with one ormore further embodiments of the invention;

[0045]FIG. 24 illustrates a closure device having frame anchor membershaving a generally “G” shaped frame structure in accordance with one ormore further embodiments of the invention;

[0046]FIG. 25 is a perspective view of a two-dimensional closure devicewith anchor members having an elongate oval configuration in accordancewith one or more further embodiments of the invention;

[0047]FIG. 26 is a cross-sectional end view taken along line 26-26 ofthe two-dimensional closure device of FIG. 25;

[0048]FIG. 27 is a schematic view of the two-dimensional closure deviceof FIG. 25 deployed at a delivery site in vivo;

[0049]FIG. 28 is a schematic end view of a three-dimensional closuredevice with anchor members having an elongate oval configuration inaccordance with one or more further embodiments of the invention;

[0050]FIG. 29 is a schematic end view of a three-dimensional closuredevice with anchor members having an elongate oval configuration inaccordance with one or more further embodiments of the invention;

[0051]FIG. 30 is a schematic end view of a three-dimensional closuredevice with anchor members having an elongate oval configuration inaccordance with one or more further embodiments of the invention;

[0052]FIG. 31 is a schematic end view of a three-dimensional closuredevice with anchor members having an elongate oval configuration inaccordance with one or more further embodiments of the invention;

[0053]FIG. 32 is a schematic view of the three-dimensional closuredevice of FIG. 29 deployed at a delivery site in vivo;

[0054]FIG. 33 is a perspective view of a two-dimensional closure devicein accordance with one or more further embodiments of the invention;

[0055]FIG. 34 is a cross-sectional view taken along line 34-34 of thetwo-dimensional closure device of FIG. 33;

[0056]FIG. 35 is a perspective view of a two-dimensional closure devicein accordance with one or more further embodiments of the invention;

[0057]FIG. 36 is a cross-sectional end view taken along line 36-36 ofthe two-dimensional closure device of FIG. 35;

[0058]FIG. 37 is a schematic perspective view of the two-dimensionalclosure device of FIGS. 25 and 26 in a collapsed state and inserted intoa catheter;

[0059] FIGS. 38-41 are schematic views of a method for delivering aclosure device to an intended delivery site in vivo according to one ormore further embodiments of the invention;

[0060]FIG. 42 is a schematic view of a method for repositioning aclosure device at a delivery site in vivo according to one or morefurther embodiments of the invention;

[0061] FIGS. 43-46 are schematic views of a method for retrieving aclosure device from a delivery site in vivo according to one or morefurther embodiments of the invention;

[0062]FIG. 47 is a perspective view of a two-dimensional closure devicein accordance with one or more further embodiments of the invention;

[0063]FIGS. 48A and 48B are perspective views of a two-dimensionalclosure device with anchor members having an elongate oval configurationin accordance with one or more further embodiments of the invention;

[0064]FIG. 49A is a perspective view of a two-dimensional closure devicewith anchor members having and elongate oval configuration in accordancewith one or more further embodiments of the invention; and

[0065]FIG. 49B is a schematic view of the two-dimensional closure deviceof FIG. 48A deployed at a delivery site in vivo.

[0066]FIG. 50 is a perspective view of a two-dimensional closure devicewith anchor members having an elongate oval configuration in accordancewith one or more further embodiments of the invention; and

[0067]FIG. 51 is a schematic view of the two-dimensional closure deviceof FIG. 49 deployed at a delivery site in vivo.

DETAILED DESCRIPTION OF EMBODIMENTS

[0068] Various embodiments of the present invention are directed tomethods and devices for closing septal defects such as PFOs, primarilyby eliciting a healing response at the defect. The device may havevarious configurations that, in general, include an anchor member oneach side of the septal defect with at least one connecting memberbetween the anchor members that joins the anchor members. The at leastone connecting member may have one of several configurations thatpromotes a healing response in the defect.

[0069] As shown in FIG. 2, a PFO closure device 18 in accordance withone or more embodiments of the present invention includes a distalanchor component or member 20 (which can be placed on the left atrialside of the PFO), a proximal anchor member 22 (to fix the device inplace), a proximal attachment point 24 (for attachment and release froma catheter), and a central connecting member 26 (which can, for example,be a simple suture in accordance with this embodiment).

[0070] In some embodiments, the distal anchor, the proximal anchor, andthe connecting member are bioresorbable. These components can befabricated from either a single bioresorbable polymer or by a laminatedcomposite of two or more materials to provide a unique mix of propertiessuch as, for example, anchor members having stiff centers and flexibleedges, and blood contacting surfaces having controlled porosity orsurface texture to promote fast and thorough endothelialization, whileminimizing thrombosis. In addition, the tissue-contacting surface of theanchors can be designed to provide added stability by, for example,being roughened.

[0071] The distal anchor 20 is an elongated, preferably generallycylindrical, thin bar-like member with rounded, arcuately shaped ends.The tissue contacting surface of the anchor can be generally flattenedto increase tissue surface contact. In size, the distal anchor componentmight, for example, be 15-30 mm long and 2 mm in diameter with acircular cross-section. The proximal anchor 22 can be of similardimensions and shape, although it can be shorter in overall length.

[0072] Other distal and proximal anchor structures are also possible.For example, the anchors can be formed of a generally flat materialrolled to form a cylindrical shape as described below with respect tothe embodiments of FIGS. 20 and 21.

[0073] For delivery and deployment, the distal anchor 20 and proximalanchor 22 are positioned to be generally aligned in a longitudinal,end-to-end manner within a delivery sheath or catheter 28 as shown inFIG. 3. These components, with the flexible connecting member 26,traverse the catheter or delivery sheath in this longitudinalorientation. The catheter or delivery sheath is inserted between septumprimum and septum secundum into the left atrium 18, and the distalanchor component 20 is ejected. Then, the catheter or delivery sheath 28is withdrawn into the right atrium, and the proximal anchor 22 isejected. The flexible central connecting member 26 extends betweenseptum primum and septum secundum to join the distal anchor 20 and theproximal anchor 22. Once ejected, the distal anchor and proximal anchorgenerally self-orientate to be essentially perpendicular to the axis ofthe central connecting member and in generally parallel planes to oneanother. The exact orientation will be governed by the individualpatient's anatomy. The terms “withdrawn” and “ejected” are relative andare intended to generically describe the relative movement of the devicewith respect to the delivery catheter.

[0074] An alternate delivery method for this device can be to deploy itdirectly through the septum primum as opposed to through the PFO.

[0075] The method of attaching the central connecting member 26 to theanchor and stop mechanism 22 to permit the distal anchor and theproximal anchor to be drawn together could be, for example, via afriction fit or via a slip knot on the central connecting member. If aslip knot is used, the free end of the suture proximal to the knot canbe held remotely and released after the knot has been placed in theappropriate location.

[0076] In one or more alternate embodiments of the invention shown inFIG. 4, the central connecting member 26 is mounted to permit freesliding movement of the proximal anchor 22 relative to the centralconnecting member 26. A biasing spring 30, which may be an expandablecoil spring, can be formed at the outer end of the central connectingmember 26 to bias the proximal anchor toward the distal anchor when bothare deployed from the catheter or sheath.

[0077] In the embodiments illustrated in FIGS. 4 and 5, a metalliccomponent may be used as the central connecting member 26 in order toprovide an appropriate stop and apply compression force to the proximalanchor 22. The metallic component could be a piece of shape memory wirethat has one end molded or laminated into the distal anchor component20. In FIG. 4, the proximal anchor 22 slides on the central connectingmember 26, and once it is deployed, the biasing spring 30 formed on theend of the shape memory wire expands to bias the proximal anchor 22toward the distal anchor 20.

[0078] In the FIG. 5 embodiment, a shape memory wire forms a hook typeanchor 32 made from two wires that exit through the center of theproximate anchor and curve in opposite directions when expanded to drawthe proximate anchor toward the distal anchor.

[0079] While the embodiments of FIGS. 4 and 5 can leave a permanentforeign body when the bioresorbable components dissolve (if, forexample, a metallic component is used as the central connecting member26), one advantage of these devices is that no thrombogenic tissuescaffold (usually a vascular material) is placed on the left atrialside. Thrombus forming on the LA side of a PFO closure device can bereleased into the systemic circulation causing an embolic event withinthe coronary arteries, cerebral circulation, or distally in thevasculature, and most vascular graft materials utilized to close PFOsare highly thrombogenic.

[0080] The PFO closure devices may need to be capable of x-rayvisualization and use with radiopaque fillers or marker bands, which maybe fabricated from noble metals such as platinum or gold. These markerscan be attached using a variety of common methods such as, for example,adhesive bonding, lamination between two layers of polymer, or vapordeposition.

[0081]FIGS. 6A and 6B illustrate a closure device 50 in accordance withone or more further embodiments of the invention. The device 50 includesproximal and distal anchor members 52, 54 connected with a flexible (andpreferably stretchable elastomeric) center joint or connecting element56. The anchor members 52, 54 are preferably cylindrical in shape withrounded ends. In size, the distal anchor member 54 might, for example,be about 15-30 mm long and about 2 mm in diameter with a circularcross-section. The proximal anchor 52 can be of similar dimensions andshape, although it can be shorter in overall length. The anchor members52, 54 are preferably made from a relatively rigid (preferablybioresorbable) polymer (regular or shape memory), or biological tissue.Biocompatible metal can also be used.

[0082] Other distal and proximal anchor structures are also possible.For example, the anchors can be formed of a generally flat materialrolled to form a cylindrical shape as described below with respect tothe embodiments of FIGS. 20 and 21.

[0083] The center joint 56 of the FIG. 6 device (as well as the centerjoints of the devices shown in FIGS. 7-10, 12-18, and 21-24) arepreferably elastomeric and resilient and are made from thrombogenic orinflammatory materials including, for example, polyester, biologicaltissue, bioresorbable polymer, small diameter springs (e.g., Nitinolsprings), or spongy polymeric material. Alternatively, the center jointcan be made of multiple strands of material 58 such as, for example,polymer fibers as shown in the closure device 60 of FIGS. 7A and 7B. Thecenter joint can be textured, porous or in a form of a single ordouble-sided hook material such as Velcro. These kinds of surfacesproduce inflammatory responses and therefore, promote faster tissueingrowth and faster defect closure. The entire device or parts of it canbe made from bioresorbable polymers.

[0084]FIG. 8A and 8B are front and side views, respectively, of thedevice 50 in a PFO defect. The proximal and distal anchor members 54, 52are longer than the defect width, thereby inhibiting the device frombeing embolized.

[0085] In accordance with further embodiments of the invention, aclosure device can include a delivery/removal mechanism to facilitatedevice delivery, removal or repositioning. A device 70 shown in FIGS. 9Aand 9B includes a removal string 72 and a delivery string 74. Theremoval string is movably secured and slides freely inside of theproximal anchor member 76. The string extends from one end of theproximal member 76 and is fixed to an opposite end of the distal anchormember 78. By pulling on the free end of the removal string 72, thewhole device 70 can be collapsed and pulled into the delivery sheath 79as shown in FIG. 9A. The strings can, for example, be sutures or wiressuch as Nitinol wire.

[0086] The delivery and removal strings are manipulated separately inorder to deploy or remove the device. FIGS. 9C-E illustrate devicedeployment using the delivery string 74, which is preferably attachedgenerally to the center of the proximal anchor member 76. The deliverysheath 79 containing the device 70 is first inserted between the septumprimum and septum secundum into the left atrium as shown in FIG. 9C. Asshown in FIG. 9D, the distal anchor 78 is then ejected from the deliverycatheter 79. Tension is then applied to the delivery string 74, and thedelivery sheath is withdrawn into the right atrium and the proximalanchor 76 is ejected. Applying tension to the delivery string enablesthe proximal anchor 76 to be properly deployed in the right atrium, andkeeps the anchor 76 from being ejected into the left atrium. Uponsuccessful deployment of the device 70, both strings are released andthe delivery system is withdrawn. No tension is applied to the removalstring during delivery.

[0087] FIGS. 9F-H illustrate removal of the device 70. As shown in FIG.9F, tension is applied to the removal string, while the delivery sheath79 is moved toward the device 70. The applied tension causes theproximal anchor 76 to be withdrawn into the delivery sheath as shown inFIG. 9G. The distal anchor 78 is also withdrawn into the delivery sheathas further tension is applied to the removal string. The device can thenbe redeployed if desired or removed.

[0088] Alternatively, the delivery string 74 can be omitted, and theremoval string 72 can be used for both device deployment and removal.The delivery sheath 79 containing the closure device is first insertedbetween septum primum and septum secundum into the left atrium in asimilar manner to that shown in FIG. 9C. The distal anchor 78 is thenejected from the delivery catheter 79 in a similar manner to that shownin FIG. 9D. Tension is applied to the removal string 72, and thedelivery sheath is withdrawn into the right atrium, and the proximalanchor 76 is ejected. Applying tension to the removal string enables theproximal anchor 76 to be properly deployed in the right atrium and keepsthe proximal anchor 76 from being ejected into the left atrium. Theelasticity of the center joint connecting the anchor members helpsproperly position the proximal anchor at the defect. Upon successfuldeployment of the closure device, the string 72 is released and thedelivery system is withdrawn.

[0089] As shown in FIGS. 10A and 10B, in another embodiment, strings 80(suture, Nitinol wire, etc.) are attached to both ends of the proximalanchor member 82 of a closure device 84. Both anchor members areflexible and can fold as shown in FIG. 10A in order to be delivered toor removed from the defect.

[0090] In accordance with a further embodiment of the invention, asshown in FIGS. 11A and 11B, each of the proximal and distal anchormembers can include two elements 90 separated by an elastic hinge 92.The elastic hinge 92 can facilitate folding of the members as shown inFIG. 11B. The hinge 92 can be molded or made from a material such as,for example, Nitinol or other shape memory materials, which can be adifferent material from the elements 90.

[0091] In accordance with some embodiments of the invention, an entireclosure device can be made from a single sheet of a material as shown,for example, in the closure device 100 of FIG. 12. Two opposite ends ofthe sheet can be rolled to form the proximal and distal anchor members.Glue or heat bonding can be used to maintain the rolled-up configurationof the anchor members 102, 104.

[0092] As shown in FIG. 13, in accordance with some further embodimentsof the invention, one or both anchor members 110, 112 of a closuredevice 114 can be inflatable. The anchor members can be inflated with,for example, saline or other physiological fluid during or before thedelivery of the device. A tube 116 can communicate with cavities in theanchor members. An inlet 118 can be provided at one of the members forintroducing fluid therein.

[0093] In accordance with some further embodiments of the invention, awire 120 such as, for example, an S-shaped wire, can be provided toconnect the proximal and distal anchor members 122, 124 of a device 126as shown in FIG. 14. The wire can be used to provide additional clampingforce while the device is in a PFO defect. Other wire shapes are alsopossible.

[0094] In accordance with further embodiments of the invention, one ormore frame structures can be used as the anchor members of a closuredevice. For example, FIG. 15 shows a closure device 130 having a framestructure 132. Also, FIG. 16 shows a closure device 136 having frames138, 139. The frames can be, for example, a metal (e.g., Nitinol wire)or polymer frame.

[0095] FIGS. 17-19 illustrate closure devices in accordance with somefurther embodiments of the invention. A closure device 140 shown in FIG.17 includes anchor members 142, 144 having a frame structure. The frameshape can be polygonal as shown in the figure or it can alternatively bea circular shape. Other frame shapes are also possible as, for example,will be described below with respect to FIGS. 22-24.

[0096] A recovery suture can be attached to opposite ends of theproximate anchor member 142 to collapse the anchors for delivery in acatheter 146 as shown in FIG. 18 or for retrieval or repositioning. Theanchor members can be made from a metal, preferably Nitinol, orpolymers. Alternatively, as shown in FIG. 19, an anchor member 148 caninclude both metal and polymer components.

[0097] In accordance with one or more further embodiments of theinvention, the distal and proximal anchors can be formed of a flatsheet-like member rolled to form a cylindrical shape as shown, forexample, in the device 170 of FIG. 20A. The anchors 172, 174 can unrollto form sheet-like members when deployed, as shown generally in FIG.20B. The sheet-like member can be made of a material having shape memoryproperties such as, for example, shape memory polymeric materials.Alternately, the sheet-like member can include metal struts made ofshape memory metals such as, for example, Nitinol or Nitinol alloys. Theshape memory materials allow the device to be delivered in a deliverysheath or catheter with the anchors in the rolled configuration of FIG.20A. The anchors attain the sheet-like geometry of FIG. 20B oncedeployed due to their shape memory properties. The anchor members 172,174 can be connected to each other with a connecting member 176, whichcan, for example, be a suture similar to that used in the FIG. 2 device.

[0098]FIGS. 21A and 21B illustrate a closure device 180 having rolledanchor members 182, 184, which are similar to the anchor members 172,174 of the device of FIGS. 20A and 20B. The anchors 182, 184 areconnected to each other by a connecting member or joint 186, which canbe a sheet of flexible material similar to the connecting memberspreviously described with respect to FIGS. 6 and 7.

[0099]FIG. 22A illustrates a closure device 200 in accordance with oneor more further embodiments of the invention. The device 200 includesdistal and proximal anchor members 202, 204, each of which has apolygonal or circular frame structure. The anchor members are connectedby a connecting member 206, which can be made from a flexible materialsimilar to that previously described in connection with FIGS. 6 and 7.The connecting member 206 can be made of two sheets of flexible materialconnected at their centers, generally forming an “X” shape in the sideview of the device. As shown in FIG. 22B, the proximal anchor member 204can include one or more recovery wires or sutures attached to the framestructure for use in device deployment of recovery. FIG. 22C illustratesthe device 200 as deployed.

[0100]FIGS. 23 and 24 illustrate closure devices 220, 230, respectively,in accordance with further embodiments of the invention. Each device220, 230 includes distal and proximal anchor members having a framestructure. The anchor members are connected by a flexible joint 222,which can be made from a flexible material similar to that previouslydescribed in connection with FIGS. 6 and 7. The FIG. 23 device 220includes distal and proximal anchor members 224, 226 generally having a“+” shape. The FIG. 24 device 230 includes distal and proximal anchormembers 232, 234 generally having a “G” shape.

[0101] In still further embodiments of the closure device 250 accordingto the present invention, the distal and/or proximal anchor members 252and 254, respectively, may be formed of cylindrical structures, splitalong the central portion of their length to provide elongate ovals(i.e., an “open-mouthed” configuration) as shown in FIGS. 25-27. In thiselongate oval configuration, arcs 256 and 258 are joined by ends 251,253 and 255, 257, respectively (FIG. 25). This configuration increasesthe size and surface area of the anchor member, thereby improving thedislodgement resistance of the closure device 250. As used herein,“dislodgement resistance” refers to the ability of a closure device toresist the tendency of the force applied by the unequal pressuresbetween the right atrium 10 and the left atrium 12 (i.e. the “dislodgingforce”) to separate the closure device from the septal tissue.Generally, a high dislodgement resistance is desirable.

[0102] Distal and/or proximal anchor members 252 and 254 having thiselongate oval configuration may be either two-dimensional (FIGS. 25-27)or three-dimensional (FIGS. 28-32). As shown in FIG. 28, in thethree-dimensional configuration, the arcs 258 a and 258 b of proximalanchor member 254 are predisposed to bend at an angle θ from the plane Aof the two-dimensional proximal anchor member 254. Arcs 258 a and 258 bmay bend at an angle θ either toward or away from center joint 259(FIGS. 29 and 30, respectively). In particular embodiments, both distalanchor 252 and proximal anchor 254 are three-dimensional. In suchembodiments, arcs 256 a and 256 b of distal anchor member 252 and arcs258 a and 258 b of proximal anchor member 254 may bend at the same angleθ or at different angles θ_(distal) and θ_(proximal), respectively.Further, arcs 256 a, 256 b and 258 a, 258 b may bend toward center joint259 (FIG. 29), away from center joint 259 (FIG. 30), or in oppositedirections (i.e., one toward center joint 259 and one away from centerjoint 259, as shown in FIG. 31). As shown in FIGS. 28-32, arcs 256 a,256 b and 258 a, 258 b include a straight bend; however, arcs 256 a, 256b and 258 a, 258 b may also include a curved bend such that they areconcave or convex. One skilled in the art will further recognize that,in a three-dimensional configuration, ends 251, 253 and 255, 257 mayalso be bent as described above for arcs 256 a, 256 b and 258 a, 258 b.

[0103] In some clinical applications, a three-dimensional configurationof distal anchor member 252 and/or proximal anchor member 254 may beparticularly advantageous. For example, septum primum 14 and septumsecundum 16 are typically of disparate thickness, as shown in FIG. 32.Consequently, the septal tissue in the right atrium 10 is characterizedby a step-like surface (indicated by line L_(RA)). The septal tissue inthe left atrium 12 may also be characterized by a similar step-likesurface (indicated by line L_(LA)). Insertion of a closure deviceincluding a two-dimensional anchor into a PFO surrounded by suchstep-like septal tissue often results in undesirable seating of thatanchor member against the septal tissue, in that at least one arc ofeach anchor member does not contact the septal tissue, as shown in FIG.27. However, the angled arcs of a three-dimensional anchor member maymore closely approximate the step-like surface of the septal tissue, asshown in FIG. 32. Thus, in certain clinical applications, the use of aclosure device including a three-dimensional distal anchor member 252and/or proximal anchor member 254 may provide improved seating of thedevice 250 against the septal tissue and, correspondingly, a reducedprofile of the device 250 and more effective closure of the PFO. As usedherein, “profile” refers to the degree to which closure device 250extends away from the septal tissue (i.e., septum primum 14 and septumsecundum 16) and is exposed in the atria. A device having a “lowprofile” is closely seated against the septal tissue and extends onlyslightly, if at all, into the atria. A device having a “high profile”extends away from the septal tissue and into the atria. Generally, adevice having a low profile is desirable because it is less thrombogenicin vivo. One skilled in the art will be capable of determining thoseclinical applications in which the use of three-dimensional anchormembers is appropriate.

[0104] Either or both of distal anchor member 252 and proximal anchormember 254 having the above-described elongate oval configuration mayinclude a tissue scaffold 260 extending between their two arcs 256 a,256 b and 258 a, 258 b, respectively, as shown in FIG. 25. The inclusionof tissue scaffold(s) 260 augments the area of septal tissue covered bythe anchor members 252 and/or 254. Consequently, device 250 providesimproved closure of the PFO. Moreover, tissue scaffold 260 promotesencapsulation and endothelialization of the septal tissue, therebyfurther encouraging anatomical closure of the PFO. The tissue scaffold260 may be formed of any flexible, biocompatible material capable ofpromoting tissue growth, including but not limited to, polyesterfabrics, Teflon-based materials, ePTFE, polyurethanes, metallicmaterials, polyvinyl alcohol (PVA), extracellular matrix (ECM) or otherbioengineered material, synthetic bioabsorbable polymeric scaffolds,other natural materials (e.g., collagen), or combinations of theforegoing materials. For example, the tissue scaffold 260 may be formedof a thin metallic film or foil, e.g., a nitinol film or foil, asdescribed in U.S. patent application Ser. No. 2003/0059640 (the entiretyof which is incorporated herein by reference).

[0105] Distal anchor member 252 and proximal anchor member 254 may beconnected by a flexible center joint 259 (FIG. 25). As previouslydescribed, in at least some embodiments, center joint 259 includes astretchable elastomeric material. In at least some embodiments, centerjoint 259 includes a thrombogenic or inflammatory material, such aspolyester, biological tissue, bioresorbable polymer, small diametersprings, e.g., nitinol springs, spongy polymeric material, orcombinations of the foregoing materials. In at least some embodiments,center joint 259 is textured, porous, or in the form of a single- ordouble-sided hook material, such as Velcro. These types of surfacesproduce inflammatory responses and, therefore, promote faster tissueingrowth and defect closure. In particular embodiments and as shown inFIG. 25, center joint 259 is formed of a deformable or expandable film,such as those disclosed in U.S. patent application Ser. Nos.2002/0165600 and 2002/0165576 (both of which are incorporated herein byreference). For example, center joint 259 may be formed of a shapememory film (e.g., nitinol film) or a polymeric film. Small openings471, e.g., slits or holes, may be cut in the film such that, as the filmexpands upon deployment in vivo, the openings 471 also expand (FIGS. 47Aand 47B). In this manner, the center joint 259 is rendered more flexibleand capable of expanding significantly in length without placingexcessive strain on the closure device (FIG. 47B). In some embodiments,the closure device 250 may include two flexible center joints 259 a and259 b (FIG. 33).

[0106] Center joint 259 may be of various shapes and sizes dependingupon the particular anatomy of the patient's septal tissue. For example,as shown in FIG. 25, center joint 259 may be generally rectangular. Inother embodiments, and as shown in FIG. 35, center joint 259 may beshaped generally as an “X” or hourglass when in its relaxedconfiguration. Removing material from the sides of center joint 259 toform an hourglass shape increases its flexibility in vivo. The amount ofmaterial removed from the sides of a rectangular center joint 259 toform an hourglass shape will vary depending upon the particularapplication. According to some embodiments, between one-third andtwo-thirds of a rectangular center joint 259 will be removed to form thecorresponding hourglass center joint 259. In particular embodiments,approximately one-half of a rectangular center joint 259 will be removedto form the corresponding hourglass center joint 259. In determining theprecise amount of material to remove from the sides of a rectangularcenter joint 259 to form an hourglass center joint 259, a sufficientportion of center joint 259 must be retained to promote the healingresponse of the septal tissue that it contacts in vivo. One skilled inthe art will be able to determine the precise amount of material thatmay be removed from a rectangular center joint 259 to form an hourglasscenter joint 259 suitable to the patient's septal anatomy whilesufficiently maintaining the ability of center joint 259 to promote thehealing of the septal tissue.

[0107] Center joint 259 may be connected to distal and proximal anchormembers 252 and 254, respectively (FIGS. 35 and 36), or, if present, totissue scaffolds 260 (FIG. 25). Center joint 259 may connect to tissuescaffolds 260 at their centers (FIG. 25), at a location on theirperipheries (FIGS. 33 and 34), or somewhere in between (FIG. 48A). Inparticular embodiments, center joint 259 is connected at a locationbetween the center and a periphery of tissue scaffold 260 on distalanchor member 252 and at a location between the center and oppositeperiphery of tissue scaffold 260 on proximal anchor member 254 (FIG.48A) so as to more closely approximate the angled, tunnel-like anatomyof the PFO and reduce the profile of closure device 250 in vivo (FIG.48B). For example, as shown in FIGS. 48A and 48B, center joint 260 maybe connected to the tissue scaffold 260 of distal anchor member 252 at alocation between the center of the tissue scaffold 260 and the arc 256 aand connected to the tissue scaffold 260 of proximal anchor member 254at a location between the center of tissue scaffold 260 and the arc 258b.

[0108] A closure device including a distal anchor member 252 and/orproximal anchor member 254 having an elongate oval configuration may bedeployed or retrieved if arcs 256 a, 256 b and/or 258 a, 258 b,respectively, are collapsed to reduce the profile of closure device 250such that it may be drawn into and contained within a delivery orretrieval catheter 370 (FIGS. 37-46). According to one embodiment and asshown in FIG. 25, closure device 250 may include a delivery string 371.As shown in FIG. 25, delivery string 371 is permanently attached to arc258 a of proximal anchor member 254, although one of skill in the artwill recognize that delivery string 371 may be attached anywhere onproximal anchor member 254. Delivery string 371 may be attached in anysuitable manner, for example, through a drilled hole, via glue, etc.Delivery string 371 is short (i.e., several millimeters) and as leastthrombogenic as possible. As used herein, “string” includes variousmaterials, which may be stiff or flexible. Delivery string 371terminates in a ball 377 at its free end. Closure device 250 furtherincludes a recovery ball 373 attached to recovery string 374, which isthreaded through ends 255 and 257 of proximal anchor member 254 andsubsequently attached to end 253 of distal anchor member 252. Slack 375exists in recovery string 374 between end 253 of distal anchor member252 and end 257 of proximal anchor member 254. Closure device 250 stillfurther includes a ball 372 attached to recovery string 374 andcontained between ends 255 and 257 of proximal anchor member 254. Ends255 and 257 of proximal anchor member 254 may have an inner diametergreater than that of ball 372 but are tapered such that the terminalsegment of ends 255 and 257 have a diameter smaller than that of ball372. Thus, the movement of ball 372 is constrained between ends 255 and257 of proximal anchor member 254.

[0109] Prior to deployment in vivo, device 250 must be placed withindelivery catheter 370 (FIG. 37). Device 250 may be loaded into catheter370 in any manner such that slack 375 is maintained in recovery string374 between distal anchor member 252 and proximal anchor member 254, asshown in FIG. 37. For example, device 250 may be manually loaded intocatheter 370. One skilled in the art will be capable of identifyingsuitable methods for loading device 250 into catheter 370.

[0110] One of skill in the art will, of course, recognize that themaximum amount of slack 375 in the recovery string 374 is dependent uponthe distance ball 372 may travel between ends 255 and 257 of proximalanchor member 254. Slack 375 increases as ball 372 travels closer towardthe terminus of end 257. Thus, the amount of slack 375 may be adjustedby altering the tapering of the internal diameter of ends 255 and 257.Additionally, the slit 480 splitting ends 255 and 257 of proximal anchormember 254 into arcs 258 a and 258 b may be extended toward the terminiof ends 255 and 257 so as to maximize the distance ball 372 may travelwithin proximal anchor member 254 and, correspondingly, the slack 375(FIG. 46).

[0111] Device 250 may be delivered to its intended delivery site in vivoby various methods, only one of which will be described herein. As shownin FIG. 38, the clinician holds both recovery ball 373 and delivery ball377 by suitable devices, e.g., grips 376 and 401. As used herein, theterms “ball” and “grips” are used to generically describe the deliverymechanism. One skilled in the art will recognize that the precisestructure of the delivery mechanism components may vary. Grips 376 and401 permit the clinician to apply tension or compression to deliverystring 371 or recovery string 374 as desired to properly manipulatedevice 250. Generally, during delivery of device 250 by the methoddescribed herein, tension will be applied only to delivery string 371;recovery string 374 will be held in a relaxed configuration such thatslack 375 is maintained. Once the clinician is properly holding bothrecovery ball 373 and delivery ball 377, catheter 370 is deliveredthrough the patient's vasculature to the right atrium 10 of the heart(FIG. 38). Then, as shown in FIG. 39, catheter 370 is inserted betweenseptum primum 14 and septum secundum 16 into the left atrium 12. Distalanchor member 252 is ejected into the left atrium 12 by pushing on grips401, and arcs 256 a and 256 b reassume their elongate oval configuration(FIG. 39). Catheter 370 is withdrawn between septum primum 14 and septumsecundum 16 and into the right atrium 10, such that proximal anchormember 254 is deployed into the right atrium 10 and slack 375 extendsthrough the PFO (FIG. 40). During this process, grips 401 are maintainedon delivery ball 377, and the necessary tension is applied to deliverystring 371 (FIG. 40). As shown in FIG. 40, arcs 258 a and 258 b reassumetheir elongate oval configuration upon deployment of proximal anchormember 254 into the right atrium 10, and proximal anchor member 254 maybe positioned as desired against the septal tissue using grips 401.Distal anchor member 252 and proximal anchor member 254 cooperate toapply a compressive force to septum primum 14 and septum secundum 16,thereby closing the PFO (FIG. 41). If deployment of closure device 250is satisfactory to the clinician, grips 401 release delivery ball 377,grips 376 release recovery ball 373 (FIG. 41), and catheter 370 iswithdrawn from the right atrium 10 and further withdrawn through thepatient's vasculature.

[0112] However, if, following deployment, the clinician is not satisfiedwith the position of device 250, grips 376 and grips 401 may bemaintained on balls 373 and 377, respectively, so that the device 250may be repositioned and/or retrieved. Device 250 may be repositioned byfurther manipulating the tension applied to delivery string 371 by grips401 (FIG. 42). To retrieve closure device 250, catheter 370 ispositioned against end 255 (FIG. 43). Recovery ball 373 is pulled intothe catheter 370, such that ball 372 moves to point B of end 255 andarcs 258 a and 258 b of proximal anchor member 254 are collapsed andwithdrawn into catheter 360 (FIG. 44). Upon nearing complete retrievalof proximal anchor member 254, slack 375 in string 374 is eliminated, ornearly so, and end 257 of proximal anchor member 254 and end 253 ofdistal anchor member 252 are touching, or nearly touching, such thatproximal anchor member 254 and distal anchor member 252 are aligned in alongitudinal, end-to-end manner (FIG. 44). Grips 376 continue to applytension to recovery string 374, pulling recovery ball 373 toward theproximal end of catheter 370, as shown in FIG. 45. Arcs 256 a and 256 bof distal anchor member 252 are collapsed, and distal anchor member 252is withdrawn into catheter 370 (FIG. 45). Catheter 370 is then withdrawnthrough the PFO, and into the right atrium 10 (FIG. 46).

[0113] The delivery and recovery system of device 250 may be modified invarious ways, one of which is shown in the device 490 of FIGS. 49-50.String 374 may be extended from end 255 of proximal anchor member 254toward arc 258 a, be attached to arc 258 at a point Y, further extendfrom arc 258 a to form delivery/recovery string 491, and terminate indelivery/recovery ball 492 (FIG. 49). The device 490 may be deployed asdescribed above, except that only grips 401 would be necessary holddelivery/recovery ball 492 and manipulate the tension applied todelivery/recovery string 491 during delivery. To retrieve device 490,grips 401 apply sufficient tension to delivery/recovery string 491 tobreak its connection to arc 258 a of proximal anchor member 254 at pointY (FIG. 50). By applying further tension to delivery/recovery string 374by pulling delivery/recovery ball 492 towards the proximal end of thecatheter 370, device 490 orients in a longitudinal manner and may bewithdrawn into the catheter 370 as described previously.

[0114] The closure devices described herein can optionally be used alongwith suturing or stapling techniques where the anchors or flexiblejoints of the devices can be sewn or stapled to septum primum 14 and/orseptum secundum 16 for better dislodgment resistance. Also, the flexiblejoint can, if desired, be covered with a biocompatible adhesive toadhere to the tissue or can be loaded with drugs or growth factors topromote healing. The adhesive and also certain drugs can also optionallybe stored in any cavities in the anchor members 252 and/or 254 (e.g., inthe cylindrical members of FIGS. 6 and 7) and released after deployment.Radiopaque markers can also be attached to the closure devices forbetter visualization during the implantation procedure. One skilled inthe art will recognize that a variety of visualization techniques may beused, including fluoroscopy and magnetic resonance imaging (MRI).

[0115] The various closure devices described herein may further includea number of advantageous features. The closure devices preferably havean atraumatic shape to reduce trauma during deployment or removal. Inaddition, the devices can be self-orienting for ease of deployment.Furthermore, because of the flexible center joint, the devices generallyconform to the anatomy instead of the anatomy conforming to the devices,which is especially useful in long tunnel defects. In addition, thedevices can preferably be repositioned and/or removed during delivery.The devices also generally have a relatively low profile afterdeployment. The flexible center joint 259 of the devices can encouragefaster tissue ingrowth and therefore, faster defect closure.Furthermore, there are generally no exposed thrombogenic components inthe left 12 and right 10 atria. Still further, the devices mayadvantageously include bioresorbable components, which will disappearfrom the body over time.

[0116] One skilled in the art will recognize that the features of anyembodiment described herein may be combined with those of any otherembodiment described herein.

[0117] Other benefits of the devices described herein include thepossible use of a relatively small diameter delivery sheath, use of areduced amount, or no, metal mass in the device, ease of manufacturing,cost effectiveness, and overall design simplicity.

[0118] Having described preferred embodiments of the present invention,it should be apparent that various modifications may be made withoutdeparting from the spirit and scope of the invention, which is definedin the claims below.

What is claimed is:
 1. A device for closing a defect in septal tissue,comprising: a first side adapted to be disposed on one side of theseptal tissue and a second side adapted to be disposed on the oppositeside of the septal tissue, said first and second sides connected by atleast one center joint, wherein each of said first and second sidesincludes an anchor member, and wherein the anchor member of at least oneof said first and second sides comprises a generally cylindrical membersplit along the central portion of its length to form an elongate oval.2. The device of claim 1, wherein said at least one center joint extendsthrough the defect in the septal tissue when said device is deployed atits intended delivery location.
 3. The device of claim 2, wherein saidfirst and second sides cooperate to provide a compressive force to theseptal tissue surrounding the defect.
 4. The device of claim 1, whereineach of said first and second sides comprises a generally cylindricalmember split along the central portion of its length to form an elongateoval.
 5. The device of claim 4, wherein said first and second anchormembers are three-dimensional.
 6. The device of claim 1, wherein saidanchor members include a material selected from the group consisting ofmetals, polymers, shape memory materials, bioresorbable materials,drug-exuding materials, and combinations of the foregoing materials. 7.The device of claim 1, wherein said at least one center joint includes astretchable elastomeric material.
 8. The device of claim 7, wherein saidat least one center joint includes a shape memory material.
 9. Thedevice of claim 8, wherein said at least one center joint includesnitinol.
 10. The device of claim 9, wherein said at least one centerjoint comprises a nitinol film.
 11. The device of claim 10, wherein saidnitinol film includes openings selected from the group consisting ofslits and holes.
 12. The device of claim 7, wherein said at least onecenter joint includes a material that promotes closure of the defect inthe septal tissue.
 13. The device of claim 12, wherein said at least onecenter joint includes a material selected from the group consisting ofthrombogenic materials, inflammatory materials, drug-exuding materials,and combinations of the foregoing materials.
 14. The device of claim 7,wherein said at least one center joint is porous.
 15. The device ofclaim 1, wherein at least one of said first and second anchor membersincludes a tissue scaffold.
 16. The device of claim 15, wherein saidtissue scaffold includes a material selected from the group consistingof polyester fabrics, Teflon-based materials, ePTFE, polyurethanes,metallic materials, polyvinyl alcohol (PVA), extracellular matrix (ECM),synthetic bioabsorbable polymeric scaffolds, collagen, drug-exudingmaterials, and combinations of the foregoing materials.
 17. The deviceof claim 15, wherein each of said first and second anchor membersincludes a tissue scaffold.
 18. The device of claim 17, wherein said atleast one center joint is connected to said tissue scaffolds.
 19. Thedevice of claim 1, wherein said device is retrievable.
 20. A device forclosing a defect in septal tissue, comprising: a first side adapted tobe disposed on one side of the septal tissue and a second side adaptedto be disposed on the opposite side of the septal tissue, said first andsecond sides connected by a at least one center joint, wherein each ofsaid first and second sides includes an anchor member comprising agenerally cylindrical member split along the central portion of itslength to form an elongate oval, and wherein said first and second sidescooperate to provide a compressive force to the septal tissuesurrounding the defect when said device is deployed at an intendeddelivery location.
 21. The device of claim 20, wherein said anchormembers include a material selected from the group consisting of metals,polymers, shape memory materials, bioresorbable materials, drug-exudingmaterials, and combinations of the foregoing materials.
 22. The deviceof claim 21, wherein each of said elongate oval anchor members isthree-dimensional.
 23. The device of claim 22, wherein each of saidelongate oval anchor members is configured to minimize the septalprofile of said device.
 24. The device of claim 23, wherein the arcs ofsaid elongate oval anchor members are positioned at an angle θ from theplane of said device.
 25. The device of claim 24, wherein each of saidelongate oval anchor members is concave in shape.
 26. The device ofclaim 24, wherein said angle θ is greater than 0 degrees and less thanabout 45 degrees.
 27. The device of claim 20, wherein each of said firstand second anchor members includes a tissue scaffold.
 28. The device ofclaim 27, wherein said tissue scaffold includes a material selected fromthe group consisting of polyester fabrics, Teflon-based materials,ePTFE, polyurethanes, metallic materials, polyvinyl alcohol (PVA),extracellular matrix (ECM), synthetic bioabsorbable polymeric scaffolds,collagen, drug-exuding materials, and combinations of the foregoingmaterials.
 29. The device of claim 20, wherein said at least one centerjoint includes a stretchable elastomeric material.
 30. The device ofclaim 29, wherein said at least one center joint includes a shape memorymaterial.
 31. The device of claim 30, wherein said at least one centerjoint includes nitinol.
 32. The device of claim 29, wherein said atleast one center joint includes a material that promotes closure of thedefect in the septal tissue.
 33. The device of claim 32, wherein said atleast one center joint includes a material selected from the groupconsisting of thrombogenic materials, inflammatory materials,drug-exuding materials, and combinations of the foregoing materials. 34.The device of claim 20, further comprising a retrieval mechanism forretrieving said device from its intended delivery location.
 35. Thedevice of claim 34, wherein said retrieval mechanism reduces the profileof said device such that said device may drawn into a catheter.
 36. Thedevice of claim 35, wherein said retrieval mechanism reduces thedistance between said first and second anchor members and aligns saidfirst and second anchor members in a longitudinal orientation.
 37. Thedevice of claim 35, wherein said retrieval mechanism comprises a stringextending from one end of said first anchor member to and through saidsecond anchor member, and a ball constrained on said string within saidsecond anchor member.
 38. The device of claim 37, wherein said string isflexible.